The most popular English language keyboard in use today is the QWERTY design developed in 1872 by C. L. Sholes, which has become a worldwide standard. A typist rests his or her fingers on the home-rows keys (i.e. the fingers of the left on the letters A S D F, and the fingers of the right hand on J K L). The left hand governs operation of the left half of the keyboard while the right hand governs operation of the right half. All of the other keys are struck according to their position relative to the home-row keys.
For example, the keys for 3 and E are above the D key, while the C key is below. Therefore, these four keys may all be struck by the same finger of the left hand (i.e. the finger that usually rests on the D key).
A "shift" key is also normally provided for remapping the keyboard to attain capitals on the letter keys and various symbols on the non-letter keys.
A disadvantage of traditional two-handed QWERTY design is that the keyboard is quite large, and the keys are angularly offset.
Many prior art attempts have been made at developing a one-handed keyboard, for overcoming the disadvantages of traditional QWERTY layouts. For example, U.S. Pat. No. 4,555,193 (Stone) discloses the principle of assigning two or more letters/characters to each key of the keyboard and incorporating a modifier key to switch between the letters/characters in a one-handed layout. According to the Stone Patent, the modifier key for selecting a particular letter is the key having the same background color as the letter to be selected.
U.S. Pat. No. 4,180,337 (Otey) discloses an arrangement of keys on a keyboard in which each letter of the alphabet is represented by an individual key, with the keys being arranged in five primary rows.
U.S. Pat. No. 3,833,765 (Hilborn et al) teaches a one-handed keyboard and novel logic circuitry associated therewith for permitting data characters to be rapidly entered via a plurality of sequential key depressions which uniquely define each character. As in the aforementioned Otey Patent, the invention of Hilborn et al includes an alphabetical arrangement of letters.
U.S. Pat. No. 4,360,892 (Endfield) teaches a one-handed portable word processor in which the key arrangements are configured in the shape of letters such that the device uses only six keys which are actuated to create the shapes of letters or characters for composing a document.
U.S. Pat. No. 4,042,777 (Bequaert et al) teaches a one-handed keyboard with a predetermined spatial arrangement between the keys for providing combinations to complete a set of alphanumeric characters. To obtain any of the large number of combinations of characters, the user depresses more than one key at a time. The thumb may depress any of four keys or any two adjacent keys while a finger concurrently presses one key, two keys next to each other or positioned at the intersection of four adjacent keys to press all four at once.
U.S. Pat. No. 4,381,501 (Prame) also teaches a one-handed keyboard using a sequence recording circuit to obtain an increased number of combinations. For instance, if key B is pressed after key A, a different character will be produced then if key A is pressed after key B.
All of the above discussed prior art patents disclose the concept of a one-handed keyboard adapted to activate a large number of alphanumeric characters by a limited number of keys. However, none of the patents disclose or suggest incorporating a standard or traditional keyboard layout such as QWERTY or DVORAK. In fact, the above noted patents teach away from such an incorporation of traditional keyboard layout.